scholarly journals LRX- and FER-dependent extracellular sensing coordinates vacuolar size for cytosol homeostasis

2017 ◽  
Author(s):  
Kai Dünser ◽  
Shibu Gupta ◽  
Christoph Ringli ◽  
Jürgen Kleine-Vehn
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Plant Cell ◽  
Cell Expansion ◽  
Leucine Rich Repeat ◽  
Sensing Mechanism ◽  
Extracellular Signals ◽  
Receptor Like Kinase ◽  
Cell Wall Acidification

Cellular elongation requires the defined coordination of intra- and extracellular processes. The vacuole is the biggest plant organelle and its dimension has a role in limiting cell expansion (Löfke et al., 2015; Scheuring et al., 2016). We reveal that the increase in vacuolar occupancy enables cellular elongation with relatively little enlargement of the cytosole. It remains, however, completely unknown how the vacuolar size is coordinated with other growth-relevant processes. Intriguingly, we show that extracellular constraints impact on the intracellular expansion of the vacuole. The underlying cell wall sensing mechanism requires the interaction of the extracellular leucine-rich repeat extensin (LRX) with the receptor-like kinase Feronia (FER). Our data suggests that LRX links the plasma membrane localised FER with the cell wall, allowing this module to jointly sense and convey extracellular signals to the underlying cell. This mechanism coordinates cell wall acidification/loosening with the increase in vacuolar size, contributing cytosol homeostasis during plant cell expansion.

scholarly journals TMK-based cell surface auxin signaling activates cell wall acidification in Arabidopsis

2021 ◽  
Author(s):  
Zhenbiao Yang ◽  
Wenwei Lin ◽  
Wenxin Tang ◽  
Koji Takahashi ◽  
Hong Ren ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Cell Surface ◽  
Cell Expansion ◽  
Auxin Signaling ◽  
Molecular Evidence ◽  
Signaling Proteins ◽  
Acid Growth ◽  
Cell Wall Acidification ◽  
Growth Hypothesis

Abstract The phytohormone auxin controls a myriad of processes in plants, at least in part through its regulation of cell expansion. The "acid growth hypothesis" has been proposed to explain auxin-stimulated cell expansion for five decades, but the mechanism underlying auxin-induced cell wall acidification is poorly characterized. Auxin induces the phosphorylation and activation of the plasma membrane (PM) H+-ATPase that pumps protons into the apoplast, yet how auxin activates its phosphorylation remains elusive. Here, we show that the transmembrane kinase (TMK) auxin signaling proteins interact with PM H+-ATPases and activate their phosphorylation to promote cell wall acidification and hypocotyl cell elongation in Arabidopsis. Auxin induced TMK's interaction with H+-ATPase on the plasma membrane within 1-2 minutes as well as TMK-dependent phosphorylation of the penultimate Thr residue. Genetic, biochemical, and molecular evidence demonstrates that TMKs are required for auxin-induced PM H+-ATPase activation, apoplastic acidification, and cell expansion. Thus, our findings reveal a crucial connection between auxin and PM H+-ATPase activation in regulating apoplastic pH changes and cell expansion via TMK-based cell surface auxin signaling.

scholarly journals TMK-based cell-surface auxin signalling activates cell-wall acidification

Nature ◽  
2021 ◽  
Author(s):  
Wenwei Lin ◽  
Xiang Zhou ◽  
Wenxin Tang ◽  
Koji Takahashi ◽  
Xue Pan ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Cell Surface ◽  
Cell Expansion ◽  
Molecular Evidence ◽  
Acid Growth ◽  
Threonine Residue ◽  
Auxin Signalling ◽  
Cell Wall Acidification ◽  
Growth Hypothesis

AbstractThe phytohormone auxin controls many processes in plants, at least in part through its regulation of cell expansion1. The acid growth hypothesis has been proposed to explain auxin-stimulated cell expansion for five decades, but the mechanism that underlies auxin-induced cell-wall acidification is poorly characterized. Auxin induces the phosphorylation and activation of the plasma membrane H+-ATPase that pumps protons into the apoplast2, yet how auxin activates its phosphorylation remains unclear. Here we show that the transmembrane kinase (TMK) auxin-signalling proteins interact with plasma membrane H+-ATPases, inducing their phosphorylation, and thereby promoting cell-wall acidification and hypocotyl cell elongation in Arabidopsis. Auxin induced interactions between TMKs and H+-ATPases in the plasma membrane within seconds, as well as TMK-dependent phosphorylation of the penultimate threonine residue on the H+-ATPases. Our genetic, biochemical and molecular evidence demonstrates that TMKs directly phosphorylate plasma membrane H+-ATPase and are required for auxin-induced H+-ATPase activation, apoplastic acidification and cell expansion. Thus, our findings reveal a crucial connection between auxin and plasma membrane H+-ATPase activation in regulating apoplastic pH changes and cell expansion through TMK-based cell surface auxin signalling.

scholarly journals The Role of Brachypodium distachyon Wall-Associated Kinases (WAKs) in Cell Expansion and Stress Responses

Cells ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 2478
Author(s):  
Xingwen Wu ◽  
Antony Bacic ◽  
Kim L. Johnson ◽  
John Humphries
Keyword(s):  
Cell Wall ◽  
Stress Response ◽  
Plant Cell ◽  
Stress Responses ◽  
Cell Expansion ◽  
Plant Cell Wall ◽  
Brachypodium Distachyon ◽  
Critical Role ◽  
Cell Integrity

The plant cell wall plays a critical role in signaling responses to environmental and developmental cues, acting as both the sensing interface and regulator of plant cell integrity. Wall-associated kinases (WAKs) are plant receptor-like kinases located at the wall—plasma membrane—cytoplasmic interface and implicated in cell wall integrity sensing. WAKs in Arabidopsis thaliana have been shown to bind pectins in different forms under various conditions, such as oligogalacturonides (OG)s in stress response, and native pectin during cell expansion. The mechanism(s) WAKs use for sensing in grasses, which contain relatively low amounts of pectin, remains unclear. WAK genes from the model monocot plant, Brachypodium distachyon were identified. Expression profiling during early seedling development and in response to sodium salicylate and salt treatment was undertaken to identify WAKs involved in cell expansion and response to external stimuli. The BdWAK2 gene displayed increased expression during cell expansion and stress response, in addition to playing a potential role in the hypersensitive response. In vitro binding assays with various forms of commercial polysaccharides (pectins, xylans, and mixed-linkage glucans) and wall-extracted fractions (pectic/hemicellulosic/cellulosic) from both Arabidopsis and Brachypodium leaf tissues provided new insights into the binding properties of BdWAK2 and other candidate BdWAKs in grasses. The BdWAKs displayed a specificity for the acidic pectins with similar binding characteristics to the AtWAKs.

scholarly journals FERONIA regulates FLS2 plasma membrane nanoscale dynamics to modulate plant immune signaling

2020 ◽  
Author(s):  
Julien Gronnier ◽  
Christina M. Franck ◽  
Martin Stegmann ◽  
Thomas A. DeFalco ◽  
Alicia Abarca Cifuentes ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Complex Formation ◽  
Cell Surface ◽  
Single Particle Tracking ◽  
Receptor Kinase ◽  
Leucine Rich Repeat ◽  
Immune Signaling ◽  
Receptor Complexes ◽  
Nanoscale Dynamics

ABSTRACTCell surface receptors survey and relay information to ensure the development and survival of multicellular organisms. In the model plant Arabidopsis thaliana, the Catharanthus roseus RLK1-like receptor kinase FERONIA (FER) regulates myriad of biological processes to coordinate development, growth and responses to the environment. We recently showed that FER positively regulates immune signaling by controlling the ligand-induced complex formation between the leucine-rich repeat receptor kinase (LRR-RK) FLAGELLIN SENSING 2 (FLS2) and its co-receptor BRASSINOSTEROID INSENSITIVE 1-ASSOCIATED KINASE 1/SOMATIC EMBRYOGENESIS RECEPTOR KINASE 3 (BAK1/SERK3). In this context, FER function is inhibited by binding of its peptide ligand RAPID ALKALINIZATION FACTOR 23 (RALF23). However, the mechanisms by which FER regulates FLS2-BAK1 complex formation remain unclear. Here, we show that FER-dependent regulation of immune signaling is independent of its kinase activity, indicating that FER rather plays a structural role. FER has been proposed to bind directly to the plant cell wall, but we found that a FER mutant unable to bind pectin is still functional in regulating immune signaling. Instead, FER- and cell wall-associated LEUCINE RICH REPEAT-EXTENSIN proteins are required for this regulation. Using high-resolution live-imaging and single-particle tracking, we observed that FER regulates FLS2 plasma membrane nanoscale dynamics, which may explain its role in controlling ligand-induced FLS2-BAK1 association. We propose that FER acts as an anchoring point connecting cell wall and plasma membrane nano-environments to enable the nucleation of pre-formed receptor/co-receptor complexes at the cell surface.

scholarly journals Cellulose synthase complexes display distinct dynamic behaviors during xylem transdifferentiation

2018 ◽  
Vol 115 (27) ◽  
pp. E6366-E6374 ◽  
Author(s):  
Yoichiro Watanabe ◽  
Rene Schneider ◽  
Sarah Barkwill ◽  
Eliana Gonzales-Vigil ◽  
Joseph L. Hill ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Cell Expansion ◽  
Secondary Wall ◽  
Transition Period ◽  
Cellulose Synthase ◽  
Wall Thickening ◽  
Cellulose Synthesis ◽  
Primary Wall ◽  
Dynamic Behaviors

In plants, plasma membrane-embedded CELLULOSE SYNTHASE (CESA) enzyme complexes deposit cellulose polymers into the developing cell wall. Cellulose synthesis requires two different sets of CESA complexes that are active during cell expansion and secondary cell wall thickening, respectively. Hence, developing xylem cells, which first undergo cell expansion and subsequently deposit thick secondary walls, need to completely reorganize their CESA complexes from primary wall- to secondary wall-specific CESAs. Using live-cell imaging, we analyzed the principles underlying this remodeling. At the onset of secondary wall synthesis, the primary wall CESAs ceased to be delivered to the plasma membrane and were gradually removed from both the plasma membrane and the Golgi. For a brief transition period, both primary wall- and secondary wall-specific CESAs coexisted in banded domains of the plasma membrane where secondary wall synthesis is concentrated. During this transition, primary and secondary wall CESAs displayed discrete dynamic behaviors and sensitivities to the inhibitor isoxaben. As secondary wall-specific CESAs were delivered and inserted into the plasma membrane, the primary wall CESAs became concentrated in prevacuolar compartments and lytic vacuoles. This adjustment in localization between the two CESAs was accompanied by concurrent decreased primary wall CESA and increased secondary wall CESA protein abundance. Our data reveal distinct and dynamic subcellular trafficking patterns that underpin the remodeling of the cellulose biosynthetic machinery, resulting in the removal and degradation of the primary wall CESA complex with concurrent production and recycling of the secondary wall CESAs.

scholarly journals LRX Proteins play a crucial role in pollen grain and pollen tube cell wall development

2017 ◽  
Author(s):  
Tohnyui Ndinyanka Fabrice ◽  
Hannes Vogler ◽  
Christian Draeger ◽  
Gautam Munglani ◽  
Shibu Gupta ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Pollen Tube ◽  
Protein Interactions ◽  
Molecular Techniques ◽  
Fine Tuning ◽  
Cell Wall Formation ◽  
Leucine Rich Repeat ◽  
Biophysical Parameters ◽  
Wall Formation

AbstractLeucine-rich repeat extensins (LRXs) are chimeric proteins containing an N-terminal leucine-rich repeat (LRR) and a C-terminal extensin domain. LRXs are involved in cell wall formation in vegetative tissues and required for plant growth. However, the nature of their role in these cellular processes remains to be elucidated. Here, we used a combination of molecular techniques, light microscopy, and transmission electron microscopy to characterize mutants of pollen-expressed LRXs in Arabidopsis thaliana. Mutations in multiple pollen-expressed lrx genes causes severe defects in pollen germination and pollen tube (PT) growth, resulting in a reduced seed set. Physiological experiments demonstrate that manipulating Ca2+ availability partially suppresses the PT growth defects, suggesting that LRX proteins influence Ca2+-related processes. Furthermore, we show that LRX protein localizes to the cell wall, and its LRR-domain (which likely mediates protein-protein interactions) is associated with the plasma membrane. Mechanical analyses by cellular force microscopy and finite element method-based modelling revealed significant changes in the material properties of the cell wall and the fine-tuning of cellular biophysical parameters in the mutants compared to the wild type. The results indicate that LRX proteins might play a role in cell wall-plasma membrane communication, influencing cell wall formation and cellular mechanics.

PLANT CELL MORPHOGENESIS: Plasma Membrane Interactions with the Cytoskeleton and Cell Wall

1997 ◽  
Vol 13 (1) ◽  
pp. 697-743 ◽  
Author(s):  
John E. Fowler ◽  
Ralph S. Quatrano
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Plant Cell ◽  
Cell Morphogenesis ◽  
Membrane Interactions

scholarly journals A trimeric CrRLK1L-LLG1 complex genetically modulates SUMM2-mediated autoimmunity

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Yanyan Huang ◽  
Chuanchun Yin ◽  
Jun Liu ◽  
Baomin Feng ◽  
Dongdong Ge ◽  
...  
Keyword(s):  
Cell Death ◽  
Plasma Membrane ◽  
Catharanthus Roseus ◽  
Nucleotide Binding ◽  
Mapk Cascade ◽  
Leucine Rich Repeat ◽  
Mapk Kinase ◽  
Trimeric Complex ◽  
Cell Death Pathway ◽  
Receptor Like Kinase

Abstract Cell death is intrinsically linked with immunity. Disruption of an immune-activated MAPK cascade, consisting of MEKK1, MKK1/2, and MPK4, triggers cell death and autoimmunity through the nucleotide-binding leucine-rich repeat (NLR) protein SUMM2 and the MAPK kinase kinase MEKK2. In this study, we identify a Catharanthus roseus receptor-like kinase 1-like (CrRLK1L), named LETUM2/MEDOS1 (LET2/MDS1), and the glycosylphosphatidylinositol (GPI)-anchored protein LLG1 as regulators of mekk1-mkk1/2-mpk4 cell death. LET2/MDS1 functions additively with LET1, another CrRLK1L, and acts genetically downstream of MEKK2 in regulating SUMM2 activation. LET2/MDS1 complexes with LET1 and promotes LET1 phosphorylation, revealing an intertwined regulation between different CrRLK1Ls. LLG1 interacts with the ectodomain of LET1/2 and mediates LET1/2 transport to the plasma membrane, corroborating its function as a co-receptor of LET1/2 in the mekk1-mkk1/2-mpk4 cell death pathway. Thus, our data suggest that a trimeric complex consisting of two CrRLK1Ls LET1, LET2/MDS1, and a GPI-anchored protein LLG1 that regulates the activation of NLR SUMM2 for initiating cell death and autoimmunity.

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